Question

The volume of water in a vase is proportional to the depth
of the water. When there are 63 mL of water in the vase,
the depth is 7 cm. How much water is in the vase when
the depth is 9 cm?

A: 49 mL
B: 810 mL
C: 108 mL
D: 81 mL

Answer 1

Step-by-step explanation:

$\frac{63}{7}=\frac{l}{9}$

$l=81\text{ ml}$

Answer 2

Answer:

D

Step-by-step explanation:

We are given that the volume of water in a vase is proportional to the depth of the water. In other words, we can write that:

$\displaystyle V = kd$

Where V is the volume, d is the depth of the water, and k is the constant of proportionality.

When there are 63 mL of water in the vase, the depth is 7 cm. Hence, V = 63 when d = 7:

$\displaystyle (63) = k(7)$

Solve for k:

$\displaystyle k = \frac{63}{7} = 9$

Hence, our equation is:

$V = 9d$

Then when the depth of the vase is 9 cm:

$\displaystyle V = 9(9) = 81\text{ mL}$

There will be 81 mL of water in the vase.

Hence, our answer is D.